This invention relates to certain revetment structures and to a jacket for protecting rope, cable, chain or other connecting means utilized in those revetment structures.
Revetment structures frequently comprise forms, which may be blocks or grids formed of precast concrete or other material, which forms are interconnected and flexibly bound to one another by rope, cable, chain or other connecting means which pass through holes, tunnels or openings in the blocks or grids. Such revetment structures are disclosed in my U.S. Pat. No. 4,370,075, issued on Jan. 25, 1983 mentioned above. These revetment structures are typically used for stablization of banks of streams and rivers, levies, river bottoms, shores, ditches, channels, canals and other earthen structures, and for protection of these structures against water or wind erosion.
Because these revetment structures are continuously exposed to forces caused by waves and ground movement, the blocks or grids forming them shift or change positions in relation to one another. Consequently, any connecting means penetrating these blocks or grids will wear against the block or grid surfaces and suffer abrasion. Furthermore, these revetment structures and their connecting means are continually exposed to sunlight. Portions of the sunlight spectrum, particularly ultraviolet light, cause degradation and deterioration of certain materials typically used in these connecting means, such as polyethylene, polypropylene, polyvinyl chloride and other synthetic or polymeric materials. Furthermore, scouring and abrasion action by salt water, sand, ice and other elements of the environment cause degradation and deterioration. As these synthetic or polymeric materials are increasingly used to fabricate connecting means for use in revetment structures because of their inertness, low weight and high tensile strength, their degradation and deterioration caused by abrasion, sunlight and the environment becomes increasingly a larger problem.
Prior attempts to minimize or prevent at least a portion of this degradation or deterioration include the placement of substantially tubular plastic inserts in the mold in which the blocks or grids forming revetment structures are cast. Such inserts are fixed within the blocks or grids, however, and their edges may abrade and cut the connecting means. Furthermore, such inserts do not protect the portions of the connecting means extending between the blocks or grids which are exposed to sunlight and the environment or achieve other features and benefits of the present invention.